Not applicable.
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Not applicable.
The invention presented here has the object of a system for manufacturing articles made of latex having a constant or variable thickness, such as pillows, bolsters, cushions, mattresses, etc.
A system is already known for manufacturing articles of latex foam rubber that make up a deformable wall, constructed in a closed loop that forms the molding area on the upper side, which is first dragged over itself through a latex foam rubber fitting station, then through a tunnel vulcanizer and finally, through a station for collecting the vulcanized product. Afterwards, the foam rubber band is cut into separate articles and these articles are subjected to washing and drying operations before they are packaged to be marketed.
One of the disadvantages of this system is that it does not make it possible to obtain finished articles at the output of the vulcanization tunnel. In addition, it is mainly designed for the manufacturing of objects having a constant thickness and can not be used for the manufacturing of pillows and mattresses having shapes designed to fit anatomical contours. Another disadvantage of this type of system is due to the principle of continuous manufacturing. In effect, this mode of manufacturing requires the use of an oven that is open on both ends in which it is difficult to vulcanize the products under high pressure and, for this reason, the time that the foam rubber stays in the oven is relatively long.
The invention presented here has the goal of solving the known problems mentioned by implementing a system for manufacturing articles made of latex which allows a substantial reduction of the time the articles stay in the oven, which greatly increases the manufacturing rates.
Another goal of the present invention is to implement a system that can be used in order to manufacture articles having different shapes and sizes, of a variable or constant thickness.
For this purpose, the system according to the invention, for the manufacturing of molded articles made of latex having a constant or variable thickness, consists of molds in each of which a latex foam rubber is intended to be introduced an oven of the autoclave type, in the vulcanization chamber of which, the molds are intended to be introduced for the vulcanization of the latex foam rubber that they contain and for the formation of the articles. This system consisting moreover of a station for filling the molds with foam rubber, a station for extracting the articles from their molds, and a unit for washing and a unit for drying articles that have been removed from the mold.
The vulcanization chamber of the oven is defined by a casing that is kept at a distance from the lateral and upper walls of the oven, and installed on the lower wall of the oven. This envelope defined by the lateral and upper walls is an enclosure in communication with the vulcanization chamber by passages arranged in the lower part of the enclosure.
The enclosure is stopped off at the end.
The oven has in its upper part at least one opening for introducing water vapor under pressure and at a high temperatures and in its lower part, at least one opening for extraction of the vapor and the evacuation of condensed water. This introduction opening is in communication with the enclosure formed around the vulcanization chamber.
The vulcanization chamber consists of an opening for loading and an opening for unloading, opposing each other, each closing by a door occurs by controlled opening and closing movements.
The enclosure arranged around the vulcanization chamber allows an introduction of the vapor at high speeds into the oven for a rapid filling. This eliminates the risk that the vapor flow at the outlet of the introduction opening comes to directly hit the molds present in the chamber and arranged over its trajectory, which guarantees a uniform vulcanization.
The casing that defines the vulcanization chamber comprises a mechanism for the deflection of the flow of the vapor.
The system according to the invention is characterized in addition by the following points.
The molds are prearranged side by side by being affixed on at least one horizontal support.
The vulcanization chamber of the oven is in the form of a rectilinear tunnel.
The filling station and the station for removing the product from the mold are arranged in a manner so that one adjoins the other, they are in alignment with each other, and they are to the side of the oven.
Along the oven, opposite the unloading opening, a zone for cooling of the molds is planned.
Between the filling station and the oven, a first transfer device is planned which is designed to receive from the filling station, the assembly of the horizontal support and molds and to introduce this assembly into the vulcanization chamber of the oven by passing it through the loading opening.
The oven is equipped in the vulcanization chamber with a mechanism for positioning the assembly of the horizontal support and the molds which ensures the support of the assembly at a distance from the longitudinal, vertical, and horizontal walls of the chamber, in a manner such that the vapor during the vulcanization which occurs after closing the doors, can be divided uniformly in the chamber of the oven around the assembly of the support frame and molds.
The doors are provided with mechanisms for longitudinal centering of the assembly of the horizontal support and molds, in the vulcanization chamber of the oven before closing the doors.
Between the cooling zone and the station for removing the product from the mold, a second transfer device is planned, which is designed to receive the assembly of the horizontal support and the molds from the cooling zone and to transfer it towards the station for removing the product from the mold.
The two transfer devices and the cooling zone are each made up of a three dimensional structure provided with at least one path for guide and support, that is horizontal, rectilinear, and parallel to the longitudinal axis of the vulcanization chamber of the oven, designed to receive the assembly of the horizontal support and molds, the cooling zone being fixed and the two transfer devices being displaceable in translation on the guide rails by the motor mechanisms, between a position aligned with the filling station and a position aligned with the vulcanization chamber of the oven for the first transfer device and between a position aligned with the cooling zone and a position aligned with the station for removing the product from the mold for the second transfer device.
The transfer mechanisms and the cooling zone are equipped with mechanisms for propulsion of the assembly of the horizontal frame and the mold on their respective paths as much in the direction of the introduction of this assembly on their path as in the direction of their removal.
Thus it is possible to manufacture the articles made of latex in a quasi-continuous manner and to use an oven in which a sizeable pressure of the vapor at a high temperature can be maintained which greatly reduces the vulcanization time and increases the rates of manufacturing.
According to another characteristic of the invention, each door for blocking the vulcanization chamber of the oven is vertically mobile in slides affixed to the oven, between a low opening position of the vulcanization chamber of the oven, and a high closing position of the vulcanization chamber of the oven. It is mobilized between these two positions by at least one motor element on the control circuit of which a safety element is located which when activated, orders the activation of the motor element in the opening direction of the door. This safety element is connected to a safety plate that is unified with the door and mounted in a manner so that it is mobile in vertical translation above the upper edge of the door in a manner so that an action on this plate, directed towards the bottom, will act on the safety element and lead the door towards its opening position.
This characteristic is favorable for improving the safety and leads to the opening of the door if this door encounters an obstacle in the course of its closing movement.
According to another characteristic of the invention, the oven around each of the openings of the vulcanization chamber is equipped with a continuous groove in which an airtight seal is arranged, forming a plunger in the groove, this groove being connected to an air source that is compressed by the action of a solenoid control valve and in the closing position of the door is supplied with compressed air via the solenoid control valve which pushes back the airtight seal against the door and ensures that it is airtight at this level. This groove is in addition connected via a second solenoid control valve to a vacuum source and is connected to this source before opening the door in such a manner that under the action of the suction created, the airtight seal is completely brought back in the groove and is freed from the door.
Due to this characteristic, any defect in the flatness of the inner side of the door or imprecise positioning of the door facing the opening will be compensated by the deformation of the seal which guarantees a good airtightedness.
According to yet another characteristic of the invention, the mechanism for positioning the assembly of the horizontal support and molds in the vulcanization chamber of the oven consists of at least two vertical frames formed by the assembly of girders and crosspieces, arranged in the vulcanization chamber of the oven, one opposite the other, parallel to the longitudinal axis of the oven, against the internal vertical sides of the chamber and by at least one horizontal path for guiding and support of the assembly of the horizontal support and molds, unified with two frames and stretching from one of the openings to the other, the path being arranged completely in the space between the frames in a manner so that the vapor passages are arranged between the path and the lateral vertical sides of the vulcanization chamber of the oven.
This device allows an equal dividing of the vapor in the oven as much above as below the horizontal support assembly and does not require vapor intakes at different levels.
According to another characteristic of the invention, the filling station comprises a horizontal container having a U-shaped cross section, open at one end and comprising along its longitudinal axis, between its vertical wings, a horizontal guide and support path of the assembly of the horizontal support and molds. This guide path is open at one end and the guide path and the guide paths of the transfer devices of the cooling zone and the vulcanization chamber of the oven is coplanar.
The arrangement of the filling device in a container allows, during filling, the recovery of the surplus of the foam rubber while the coplanar arrangement allows the easy passage of the assembly of the horizontal support and molds towards the first transfer device.
According to another characteristic of the invention, the station for removing the product from the mold is equipped with two vertical longitudinal wings set at a distance from each other between which a guide and support path of a support assembly and molds is arranged, this guide path being open at the end, the guide path and the guide paths of the transfer devices, of the filling station, of the cooling zone and the vulcanization chamber of the oven being coplanar, the guide path being arranged in alignment with the guide path of the filling station.
This coplanar arrangement makes it easier to transfer the assembly of the horizontal support and molds from one guide path to the other.
According to another characteristic of the invention, the vulcanization chamber of the oven is equipped with several guide and support paths arranged according to several levels of height in order to simultaneously receive several assemblies of horizontal support and molds. In addition, at each of these levels of height, the transfer devices and the cooling zone each contains a guide and support path of an assembly for horizontal support and molds and the filling and mold removal stations are each mobile in vertical translation between the different levels of the height under the action of a motor mechanism that is appropriate for them, this motor mechanism ensuring on the other hand their positioning at the height according to the level of height selected.
This device increases in a notable way the rates of manufacturing and best uses the capacity of the oven.
According to another characteristic of the invention, the washing unit is made of two sets of at least two pressing elements, mounted one above the other, in order to define a channel for pressing and expanding the product, containing one intake for products and one outlet for products, these pressing elements being led in rotation on themselves by a motor mechanism in order to lead the products into the channel from the intake of the channel to the outlet. The pressing elements of each set are arranged straight across from the pressing elements of the other and the pressing elements of each set are set at a distance from each other so as to make a space between them in which the molded article can become dilated, the washing unit, being equipped in addition with a mechanism for the injection of a liquid agent in the known space defined in a manner such that the latex article can be loaded with liquid washing agent during its expansion in the space.
By successive compressions of latex articles, the unit for washing plus cleaning in depth of the articles creates a dimensional stabilization of these articles.
According to another characteristic of the invention, the drying unit is made of two sets of at least two pressing elements, mounted one above the other, in order to define a channel for pressing and dilation of the products, containing a product intake and a product outlet from the washing unit, the pressing elements being led in rotation on themselves by a motor mechanism in order to lead the products into the channel, the pressing elements of each set being arranged straight across from the pressing elements of the other and the pressing elements of each set being set at a distance from each other so as to make a space between them in which the hot and dry air is introduced by a mechanism for injection so as to dry the products.
The introduction of the hot air into the space in which the product dilates allows an introduction of this air into the mass of the product and creates a drying all the way through. The air loaded with humidity will be forced out of the mass of the product during the subsequent compression of it.